[UDP-HTTP] Command-line options -h, -V, -l, -t

Add support for basic command-line options: -h (help), -V (version), and
-l and -t for the port numbers.

TODO.t2t

@@ -164,7 +164,7 @@ Work to do in OwlPS
 
 = UDP to HTTP =
 
-- Command-line options (port numbers, -v/-q, -h, -V).
+- Command-line options (-v/-q).
 
 - Delete inactive clients after a given amount of time.
 

owlps-udp-to-http/owlps-udp-to-http.c

@@ -22,9 +22,9 @@
  *   http://localhost:8080/?request=ReadSimpleResults
  * (assuming the host running this program is localhost).
  *
- * The UDP listening port is the port on which OwlPS Positioner sends
- * result by default.
- * The TCP listening port is 8080.
+ * The default UDP listening port is the port on which OwlPS Positioner
+ * sends the result by default, and the default TCP (HTTP) listening
+ * port is 8080.
  *
  * Only the last result read from the positioning server, for each
  * mobile, is memorised and provided to the HTTP client.
@@ -76,6 +76,15 @@
 
 #include <assert.h>
 
+struct {
+  uint_fast16_t result_port ;
+  uint_fast16_t http_port ;
+  int nb_connections ;
+} options = {
+  OWL_DEFAULT_RESULT_PORT, // result_port
+  DEFAULT_HTTP_PORT, // http_port
+  DEFAULT_NB_CONNECTIONS // nb_connections
+} ;
 
 char *program_name = NULL ;
 
@@ -100,12 +109,10 @@ int main(int argc, char *argv[])
   int ret = 0 ; // Program return value
   pthread_t tcp_server_thread ;
 
-  program_name = argv[0] ;
   owl_run = true ;
 
-  if (argc > 1)
-    fprintf(stderr,
-            "Sorry, this program does not take any argument yet.\n") ;
+  program_name = argv[0] ;
+  parse_command_line(argc, argv) ;
 
   /* Set up signal handlers */
   action.sa_flags = 0 ;
@@ -165,6 +172,60 @@ int main(int argc, char *argv[])
 }
 
 
+void parse_command_line(int argc, char **argv)
+{
+  parse_options(argc, argv) ;
+  check_configuration() ;
+}
+
+
+void parse_options(int argc, char **argv)
+{
+  int opt ;
+
+  while ((opt = getopt(argc, argv, OPTIONS)) != -1)
+    {
+      switch (opt)
+        {
+        case 'h' :
+          print_usage() ;
+          exit(0) ;
+        case 'l' :
+          options.result_port = strtoul(optarg, NULL, 0) ;
+          break ;
+        case 't' :
+          options.http_port = strtoul(optarg, NULL, 0) ;
+          break ;
+        case 'V' :
+          print_version() ;
+          exit(0) ;
+        default :
+          print_usage() ;
+          exit(OWL_ERR_BAD_USAGE) ;
+        }
+    }
+}
+
+
+void check_configuration()
+{
+  if (options.result_port > 65535)
+    {
+      fprintf(stderr, "Warning! result_port too high: using default"
+              " value (%d).\n", OWL_DEFAULT_RESULT_PORT) ;
+      options.result_port = OWL_DEFAULT_RESULT_PORT ;
+    }
+
+  if (options.http_port > 65535)
+    {
+      fprintf(stderr, "Warning! http_port too high: using default"
+              " value (%d).\n", DEFAULT_HTTP_PORT) ;
+      options.http_port = DEFAULT_HTTP_PORT ;
+    }
+}
+
+
+
 /*
  * Opens the UDP socket and reads from it the results sent by OwlPS
  * Positioning.
@@ -175,7 +236,7 @@ int receive_udp()
   owl_result *result ;
 
   /* Open the UDP socket */
-  udp_sockfd = owl_create_udp_listening_socket(OWL_DEFAULT_RESULT_PORT) ;
+  udp_sockfd = owl_create_udp_listening_socket(options.result_port) ;
   if (udp_sockfd < 0)
     return OWL_ERR_SOCKET_CREATE ;
 
@@ -272,7 +333,7 @@ int init_tcp_socket()
   bzero((char *) &server_addr, sizeof(server_addr)) ;
   server_addr.sin_family = AF_INET ;
   server_addr.sin_addr.s_addr = INADDR_ANY ;
-  server_addr.sin_port = htons(TCP_PORT) ;
+  server_addr.sin_port = htons(options.http_port) ;
 
 
   if (bind(tcp_sockfd, (struct sockaddr *) &server_addr,
@@ -299,7 +360,7 @@ void* tcp_server(void *NULL_value)
   char client_request[CLIENT_REQUEST_STRLEN] ;
   int request_id ;
 
-  listen(tcp_sockfd, NB_CONNECTIONS) ;
+  listen(tcp_sockfd, options.nb_connections) ;
   client_len = sizeof(client_addr) ;
 
   // Prepare the answer, assuming there is only 1 full result (an error
@@ -550,3 +611,47 @@ void free_results_list()
     }
   nb_results = 0 ;
 }
+
+
+
+/*
+ * Prints the usage message on the standard output.
+ *
+ * /!\ Don't forget to update the documentation when modifying something
+ *     here!
+ */
+void print_usage()
+{
+  printf("Usage:\n"
+         "\t%s"
+         /* " [-v | -q]" */
+         " [-l result_port]"
+         " [-t http_port]\n"
+
+         "Options:\n"
+         "\t-h\t\tPrint this help.\n"
+         "\t-V\t\tPrint version information.\n"
+         "\t-l result_port\tPort on which the results are received"
+         " (default: %d).\n"
+         "\t-t http_port\tPort on which the HTTP server listens"
+         " (default: %d).\n"
+         ,
+         program_name,
+         OWL_DEFAULT_RESULT_PORT,
+         DEFAULT_HTTP_PORT
+         ) ;
+}
+
+
+void print_version()
+{
+  printf("This is OwlPS UDP-to-HTTP, part of the Owl Positioning System"
+         " project.\n"
+         "Version: %s.\n",
+#ifdef OWLPS_VERSION
+         OWLPS_VERSION
+#else // OWLPS_VERSION
+         "unknown version"
+#endif // OWLPS_VERSION
+         ) ;
+}

owlps-udp-to-http/owlps-udp-to-http.h

@@ -21,10 +21,14 @@
 
 #include <owlps-resultreader.h>
 
-#define TCP_PORT 8080
-#define NB_CONNECTIONS 1
-#define CLIENT_MESSAGE_STRLEN 2500
 
+/* Arguments & program configuration */
+#define OPTIONS "hl:t:V" // getopt string
+
+#define DEFAULT_HTTP_PORT 8080
+#define DEFAULT_NB_CONNECTIONS 1
+
+#define CLIENT_MESSAGE_STRLEN 2500
 #define CLIENT_REQUEST_STRLEN 21
 #define SIMPLE_RESULTS_ID 1
 #define SIMPLE_RESULTS_REQUEST "ReadSimpleResults"
@@ -33,10 +37,6 @@
 #define RESULTS_REQUEST "ReadResults"
 #define RESULTS_ANSWER "Results"
 
-#ifndef OWLPS_VERSION
-# define OWLPS_VERSION "unknown version"
-#endif // OWLPS_VERSION
-
 #define ANSWER_HDR                                 \
   "HTTP/1.1 200 OK\n"                              \
   "Date: Sat, 01 Jan 0001 00:00:01 GMT\n"          \
@@ -55,6 +55,9 @@ typedef struct _results_list
 } results_list ;
 
 
+void parse_command_line(int argc, char **argv) ;
+void parse_options(int argc, char **argv) ;
+void check_configuration(void) ;
 int receive_udp(void) ;
 void store_result(owl_result *result) ;
 int init_tcp_socket(void) ;
@@ -65,6 +68,8 @@ extract_request_from_message(char client_request[CLIENT_REQUEST_STRLEN],
 void prepare_answer(int request_id) ;
 void realloc_answer(size_t new_size) ;
 void free_results_list(void) ;
+void print_usage(void) ;
+void print_version(void) ;
 
 
 #endif // _OWLPS_UDP_TO_HTTP_H_